Objectives: Estimate the effects of PSU at baseline (vs. single substance use) on the probabilities of (i) completing baseline drug treatment and (ii) contacting with the CJS after treatment at 6 months, 1-, 3- & 5-years follow-ups.
Design: Retrospective cohort based on an administrative data’s record linkage. Data: Chilean substance use treatment programs and Prosecutor’s Office through a deterministic linkage process. Ethics: We are updating an existing ethical approval by the Griffith University GU Ref No: 2022/919.
Exposure: baseline PSU (using >1 substance at admission to SUD treatment); Mediator: SUD treatment outcome (complete vs. dropout/spelled by misconduct); Outcome: contact with CJS (committing an offense that led to a condemnatory sentence).
Figure 1: Covariate balance
Figure 2: Multistate scheme
We calculated the Aalen-Johansen for transition probabilities at 6 months, 1, 3 & 5 years.
Before IPWs patients with PSU had lower rates of treatment completion (IRR=0.53 95%CI: 0.51,0.54) and greater rates of contact with the CJS vs. patients with no PSU (IRR=1.68 95%CI: 1.62,1.74).
After IPWs: patients with PSU had lower rates of treatment completion (IRR=0.77 95%CI: 0.74,0.8) but greater rates of contact with the CJS vs. patients with no PSU (IRR=1.11 95%CI: 1.06,1.17).
| Transition | Time | PSU | No PSU |
|---|---|---|---|
| From admission to contact with CJS | 6 mths | 2.2 (2.1,2.3) | 1.8 (1.7,1.9) |
| From admission to contact with CJS | 1 yr | 7.9 (7.6,8.1) | 6.6 (6.4,6.8) |
| From admission to contact with CJS | 3 yrs | 24.4 (24.0,24.7) | 20.7 (20.3,21.1) |
| From admission to contact with CJS | 5 yrs | 33.3 (32.8,33.7) | 29.5 (29.0,30.0) |
| From admission to tr.completion | 6 mths | 3.1 (2.9,3.2) | 4.0 (3.9,4.2) |
| From admission to tr.completion | 1 yr | 14.6 (14.3,14.8) | 17.6 (17.3,18.0) |
| From admission to tr.completion | 3 yrs | 23.6 (23.2,23.9) | 27.0 (26.6,27.4) |
| From admission to tr.completion | 5 yrs | 21.4 (21.0,21.8) | 24.9 (24.4,25.3) |
| From tr.completion to contact with CJS | 6 mths | 3.0 (2.0,4.0) | 2.4 (1.3,3.4) |
| From tr.completion to contact with CJS | 1 yr | 8.7 (7.5,9.8) | 5.9 (4.8,7.0) |
| From tr.completion to contact with CJS | 3 yrs | 21.1 (20.0,22.3) | 16.2 (15.1,17.3) |
| From tr.completion to contact with CJS | 5 yrs | 28.6 (27.4,29.8) | 23.0 (21.8,24.2) |
Treatment completion can reduce the risk of criminal justice involvement for people with PSU, evident at the 3-year point when most users have finished treatment. Further analysis is needed. People with PSU may need enhanced treatment to complete treatments and avoid contact with the CJS.
Funding sources: This work was funded by ANID -Millennium Science Initiative Program- N° NCS2021_003 (Castillo-Carniglia) and N° NCS2021_013 (Calvo); The authors have no conflict of interest to declare